Internal-driven compressor having a powered compressor rotor

ABSTRACT

The internal-driven compressor having a powered compressor rotor. The internal-driven compressor includes a compressor housing including a suction port and a discharge port, an internal driver including a rotor and a stator, the rotor and the stator located within the compressor housing, the stator located radially inward of the rotor, and a powered compressor rotor including an annular body extending about a center axis, wherein the rotor is fixed to the powered compressor rotor and configured to rotate the powered compressor rotor about the center axis in response to a force imparted by the stator.

TECHNICAL FIELD

The present disclosure generally pertains to pumps and gas compressors, and is more particularly directed toward a centrifugal gas compressor driven by a motor substantially within an impeller or rotating pumping member.

BACKGROUND

Integrated motor compressors exist in various forms but are still plagued by the fact that the motor and the compressor are separated devices, requiring a coupling and a relatively long shaft. Some related examples include, integrated hydroelectric generators, wind turbines with hub generators, etc. For pressurized devices such as compressors, in order to avoid seals of rotating components that seal against the atmosphere, magnetic bearings are bearings that use magnetic levitation to support a load. Magnetic bearings may support moving machinery without physical contact. For example, they can levitate a rotating shaft, providing for rotation with very low friction and no mechanical wear. Active magnetic bearings use electromagnetic suspension, and may include an electromagnet assembly, power amplifiers configured to drive the electromagnets, a controller, and sensors (e.g. gap sensors) with associated electronics. The power amplifiers drive electromagnets on opposing sides of the shaft. The sensors provide feedback to control the position of the rotor within the gap. The controller offsets the current to drive the electromagnets as the rotor deviates from its desired position.

U.S. Pat. No. 6,393,208 issued to Nosenchuck on May 21, 2002 shows a Compressor with integrated impeller and motor. In particular, the disclosure of Nosenchuck is directed toward an axial flow compressor having an impeller that has an electrically conductive ring or other conductive members disposed along a rotary path of the impeller and an impeller driver that includes a ring of magnetically permeable material extending in an arc proximate to the rotary path of the conductive portion of the impeller. The impeller driver acts as a motor stator with two core portions wound with electrically conductive coils for inducing a magnetic field in the ring and two electrically conductive pole portions spaced from the core portions. Alternating electrical current introduced to the coils imparts a rotary force to the electrically conductive ring of the impeller, causing it to transport the compressor working fluid.

The present disclosure is directed toward overcoming known problems and/or problems discovered by the inventors.

SUMMARY OF THE DISCLOSURE

An industrial gas compressor is disclosed herein. The industrial gas compressor includes a compressor housing including a suction port and a discharge port, an internal driver including a rotor and a stator, the rotor and the stator located within the compressor housing, the stator located radially inward of the rotor and a powered compressor rotor including an annular body extending about a center axis, wherein the rotor is fixed to the powered compressor rotor and is configured to rotate the powered compressor rotor about the center axis in response to a force imparted by the stator.

According to one embodiment, an internal-driven compressor is also disclosed herein. The internal-driven compressor includes a compressor housing, an internal driver including a rotor and a stator, the rotor and the stator located within the compressor housing, the stator located radially inward of the rotor, and a powered compressor rotor including an annular body extending about a center axis, an impeller bore surface, and a series of impeller vanes configured to rotate about the center axis, the impeller bore surface circumscribing the stator, wherein the rotor is fixed to and located within the impeller bore surface, and the rotor is configured to rotate the powered compressor rotor about the center axis in response to a force imparted by the stator.

According to another embodiment, a powered compressor rotor assembly for an internal-driven compressor is also disclosed herein. The powered compressor rotor assembly includes a powered compressor rotor including an annular body about a center axis, the annular body having an impeller bore surface about the center axis, the powered compressor rotor further including a series of impeller vanes extending from the annular body about the center axis, a central axle configured to support the powered compressor rotor, the central axle including at least one internal passageway, including an access port, and an internal driver including a rotor and a stator, the rotor and the stator located within powered compressor rotor, the stator located radially inward of the rotor relative to the center axis, wherein the rotor is fixed to and located within the powered compressor rotor and the stator is fixed to central axle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary internal-driven compressor.

FIG. 2 is a schematically illustrated, cutaway side view of a portion of the internal-driven compressor of FIG. 1, illustrating a single stage of compression.

FIG. 3 is a schematically illustrated, cutaway side view of a portion of the internal-driven compressor of FIG. 2, illustrating an internal driver and a compressor bearing system comprising active magnetic bearings.

FIG. 4 is a schematically illustrated, cutaway side view of a portion of the internal-driven compressor of FIG. 2, illustrating an internal driver cooling system.

FIG. 5 is a schematically illustrated, cutaway side view of a portion of an exemplary two-stage internal-driven compressor.

FIG. 6 is a schematically illustrated, cutaway side view of a portion of an exemplary multi-stage internal-driven compressor.

DETAILED DESCRIPTION

The present disclosure relates to a compressor with an integrated motor. Embodiments provide an internal-driven compressor that integrates the motor (e.g., electric motor) within the compressor itself. Here, the compressor rotor is rotatably mounted on a fixed central axle of a compressor bearing system. The impeller is driven by an electric motor rotor imbedded in the impeller bore surface. In addition, the electric motor is axially located between radial bearings.

FIG. 1 is a perspective view of an exemplary internal-driven compressor. In particular, the illustrated internal-driven compressor 700 is embodied as an axially-fed, industrial centrifugal gas compressor having a side discharge. However, this particular configuration is merely for illustration purposes, as the illustrated internal-driven compressor 700 may include any combination of singular or plural, axial, linear, and radial feeds and discharges. Likewise, the present disclosure may be applied to other types of pumps, compressors, and the like. Here and in other figures, various components and surfaces have been left out or simplified for clarity purposes and ease of explanation.

For reference, the internal-driven compressor 700 generally includes a center axis 95 about which its primary rotating components rotate. The center axis 95 may be common to or shared with various other components of the internal-driven compressor 700. All references to radial, axial, and circumferential directions and measures refer to center axis 95, unless specified otherwise, and terms such as “inner” and “outer” or “inward” and “outward” generally indicate a lesser or greater radial distance from the center axis 95, wherein a radial 96 may be in any direction perpendicular and radiating outward from center axis 95.

In addition, this disclosure may reference a forward and an aft direction. Generally, all references to “forward” and “aft” are associated with a flow direction, relative to the center axis 95, of the compressed gas. In particular, the suction end 97 (inlet) of the internal-driven compressor 700, relative to the center axis 95 is referred to as the forward end or forward direction. Accordingly, the opposite end or discharge end 98 is referred to as the aft end or direction, unless specified otherwise.

Externally, the internal-driven compressor 700 includes a compressor housing 710 and an external power supply interface 705 and a communication interface 706. Here, the communication interface 706 is illustrated as combined with the external power supply interface 705 for convenience; however, the communication interface 706 may be embodied as separate from the external power supply interface 705.

Generally, the compressor housing 710 encloses and supports internal components of the internal-driven compressor 700. Also, unlike a conventional shaft-driven compressor (requiring a dynamic seal), the external power supply interface 705 and the communication interface 706 may be statically sealed to compressor housing 710.

Additional controls for the internal-driven compressor 700 may be integrated into the internal-driven compressor 700 and/or located remotely. Moreover, communications, feedback, and control for the internal-driven compressor 700 may be interfaced independently, as discussed above. Alternately, communications, feedback, and control for the internal-driven compressor 700 may be interfaced via the external power supply interface 705.

The compressor housing 710 includes a suction port 711 and a discharge port 712. The suction port 711 interfaces with a fluid supply (not shown), and is configured to supply a fluid (e.g. working gas, process gas, pumped fluid, etc.) to the internal-driven compressor 700. Here, the fluid is a gas 15. Similarly, the discharge port 712 interfaces with a fluid discharge (not shown), and is configured to discharge the gas 15 from the internal-driven compressor 700. The compressor housing 710 may also include support legs 713, or other features to secure or physically ground the internal-driven compressor 700.

The external power supply interface 705 may include power conduit and associated power control devices configured to provide power from an external supply (not shown) into the internal-driven compressor 700. For example, the external power supply interface 705 may include electrical conduit and accessories conventionally associated with an electrical supply. Alternately, the external power source may be hydraulically or pneumatically based.

FIG. 2 is a schematically illustrated, cutaway side view of the internal-driven compressor 700 of FIG. 1, illustrating a single stage of compression. As above, various components and surfaces have been left out, cut away, and/or simplified for clarity purposes and ease of explanation. As shown, the gas 15 enters the internal-driven compressor 700 axially, is compressed in a single stage, and is subsequently collected and discharged.

Internally, the internal-driven compressor 700 includes a central axle 715, a compressor inlet 720, a compressor outlet 725, a powered compressor rotor 730, an internal driver 740, and a compressor bearing system 750. The internal driver 740 and the compressor bearing system 750 are configured to drive and support the powered compressor rotor 730 about the center axis 95, respectively. The powered compressor rotor 730 rides in a cavity within the compressor housing 710. In addition, the internal driver 740, and the compressor bearing system 750 are enclosed within the compressor housing 710. According to one embodiment, the internal-driven compressor 700 may include a powered compressor rotor assembly including portions of the powered compressor rotor 730 and the internal driver 740 coupled to the central axle 715. Moreover, the powered compressor rotor assembly may contain portions of the compressor bearing system 750.

The powered compressor rotor 730 makes up a single compression stage (as discussed below, additional stages may be used). The internal-driven compressor 700 may further include a diffuser 760 downstream of the powered compressor rotor 730. Thus, the gas 15 compressed by the powered compressor rotor 730 may then be diffused by the diffuser 760.

The compressor inlet 720 includes an upstream opening in the compressor housing 710 configured to introduce the gas 15 into the compressor flow path within the compressor housing 710. The compressor flow path may be bound in part by the compressor housing 710 (or additional structures within the compressor housing 710), and in part by the powered compressor rotor 730. Here the compressor inlet 720 is configured as an axial inlet; however, as illustrated below, in other embodiments the compressor inlet 720 may be configured as a radial or side inlet.

The compressor inlet 720 may generally include the suction port 711 and any flow distributing/shaping features downstream of the suction port 711 and upstream of the powered compressor rotor 730. For example, these features may include struts, vanes, ducting, in-line filters, etc. Also for example, the compressor inlet 720 may include a nose cover 721. The nose cover 721 is an aerostructure at the upstream end of the powered compressor rotor 730 configured to direct and condition flow entering the compression flow path. The nose cover 721 may also be configured to seal internal components from the gas, particularly where the powered compressor rotor 730 is supported by a cantilever and the compressor inlet 720 is configured as an axial inlet. The nose cover 721 may be fixed to the powered compressor rotor 730, as illustrated. Alternately, the nose cover 721 may be fixed to a structure inside the powered compressor rotor 730 (e.g., the central axle 715) or to a portion of the compressor housing 710.

The compressor outlet 725 includes a downstream opening (not shown) in the compressor housing 710 configured to discharge the gas 15 from the compressor housing 710. For example, the downstream opening may be defined by the interface between the compressor housing 710 and the discharge port 712 (see FIG. 1). Moreover, the compressor outlet 725 may generally include the discharge port 712 and any upstream flow distributing/shaping features. These upstream flow distributing/shaping features may include struts, vanes, ducting, etc. upstream of the discharge port 712 and downstream of the powered compressor rotor 730 or the diffuser 760. According to one embodiment, the compressor outlet 725 may include a plurality of outlet vanes 726 radially distributed about the center axis 95, downstream of the powered compressor rotor 730. The plurality of outlet vanes 726 may be configured to reduce swirl in the gas 15 imparted by the powered compressor rotor 730.

Here, the compressor outlet 725 is configured as a radial or side outlet. Thus, the compressor outlet 725 may also include a collector 727 at its upstream end. The collector may be integrated into the compressor housing 710, or may be joined to it as discrete unit. The collector 727 forms part of the compressor flow path, receiving the gas 15 in a radial flow and discharging the gas 15 in a linear direction. In addition, the plurality of outlet vanes 726 may be positioned and distributed at an upstream end of the collector. According to one embodiment, the collector 727 may be embodied as a discharge volute. The discharge volute is a curved funnel that increases in area as it approaches with the discharge port 712.

According to one embodiment, the powered compressor rotor 730 may be a powered impeller, having portions of the internal driver 740 embedded into or otherwise fixed to the powered impeller. In particular, the powered impeller may include a rotor 741 of the internal driver 740 embedded or otherwise fixed to the powered impeller. Thus, no drive shaft, or the like, is between the powered impeller and rotor 741 of the internal driver 740.

The powered impeller may include an annular body 731 having an impeller bore surface 732, and a series of impeller vanes 733 about an impeller axis. The annular body 731 includes an opening or impeller bore about the impeller axis. The center axis 95 may be shared or common to the impeller axis (hereinafter center axis 95) when installed. Additional features of the powered impeller may be integrated in or otherwise extend from the annular body. In some embodiments the bore of annular body may be closed at one or more locations along the center axis 95.

The impeller bore surface 732 is an inner surface of the powered impeller, circumscribing the center axis 95. Moreover, the impeller bore surface 732 may include one or more grooves, notches, slots, or other departures from a regular (e.g., cylindrical) surface, such that one or more components may be fixed to, or features may be added to the powered compressor rotor 730. For example, the impeller bore surface 732 may include a departure from a regular surface of rotation (e.g., cutout, cavity, groove, etc.), such that it is configured to engage the rotor 741. Likewise, portions of the rotor 741 may be embedded in the departure from the regular surface of rotation.

Where the internal driver 740 is an electric motor rotor, the rotor 741 may be engaged (or fixed to and located) to the impeller bore surface 732, or another portion of the annular body 731. Being fixed directly to the annular body 731, the rotor 741 is thus configured to rotate its impeller vanes 733 about the center axis 95 in direct response to an electromotive force imparted by the stator 742 of the internal driver 740. In this case, the stator 742 of the internal driver 740 is located radially inward of the rotor 741, and may be embedded or otherwise fixed to a central axle 715.

Additionally, the series of impeller vanes 733 may include flow motion transmission surfaces extending from the annular body 731. The series of impeller vanes 733 may be configured to compress and/or redirect the gas 15 along the compression flow path. For example, here, the series of impeller vanes 733 are configured to compress an axial flow of gas while redirecting it into a radial flow.

Furthermore, and as illustrated, the powered impeller may be a covered or enclosed impeller. Thus, the series of impeller vanes 733 may be part of a series of ducted vanes. The series of ducted vanes includes a shroud 734 around the series of impeller vanes 733 underneath. Accordingly, a portion of the compression flow path will be bounded by the ducted vanes and the surface of the annular body 731 between each impeller vanes 733. The shroud 734 and the series of impeller vanes 733 may be integrated as a single unit along with the annular body 731, extending inward to the impeller bore surface 732.

In this embodiment, the powered compressor rotor 730 may also include one or more seals between the compressor housing 710 and the powered impeller. The one or more seals are configured to impede the gas 15 from bypassing or flowing other than through the compressor flow path of the ducted vanes. For example, the powered compressor rotor 730 may include a shroud seal 735. The shroud seal 735 may be located on an outer circumference of the powered compressor rotor 730 proximate its upstream end. The shroud seal 735 may include a dry seal, such as a labyrinth seal. The shroud seal 735 may be machined, formed into, or otherwise fixed to the shroud 734. Alternately, the one or more seals may be machined, formed into, or otherwise fixed to the compressor housing 710.

Also in this embodiment, the powered compressor rotor 730 may further include a balance piston 736. The balance piston 736 may be located at a downstream end of the powered compressor rotor 730 (i.e., axially towards the discharge end 98). The balance piston 736 may include a balance piston seal 737 and a piston head 738. The piston head 738 may have an effective area generally defined by the annular region between its diameter and the diameter of the impeller bore surface 732 at the downstream end of the powered impeller. The balance piston 736 is set in a balance piston cavity 717 of the compressor housing 710.

The balance piston cavity 717 is ported to a lower pressure supply (e.g., upstream the powered impeller, ambient, etc.). In particular, due to the pressure rise developed through the powered impeller, a pressure difference exists such that a net thrust is created in the upstream direction. By subjecting the piston head 738 to the lower pressure supply, a pressure differential opposite to the direction of the net thrust is created. For example, the balance piston cavity 717 may be ported via a series of openings 722 (e.g., through the nose cover 721 and portions of the central axle 715) that create a flow path between a low pressure area (inlet pressure) and the balance piston cavity 717. Also for example, the balance piston cavity 717 may be ported to a lower pressure supply via a cooling system (discussed below).

The piston head 738 may be sized (e.g., choosing the diameters of the piston head 738 and impeller bore surface 732) to provide basic pressure equilibrium or balance in the axial direction. Alternately, the piston head 738 may be sized to reduce the loading on the compressor bearing system 750 in the axial direction.

According to one embodiment, the internal-driven compressor 700 may support the internal driver 740 and the compressor bearing system 750 via the central axle 715. Moreover the powered compressor rotor 730 may be rotatably mounted to the central axle 715, such that the powered compressor rotor 730 may rotate about the center axis 95. The central axle 715 is then supported by the compressor housing 710. For example, here, the central axle 715 is nonrotatably fixed to the compressor housing 710 and is cantilevered from an endcap 718 located its aft end. Alternately, the central axle 715 may be supported from both its forward and aft ends (e.g., where the internal-driven compressor 700 includes radial feed and discharge, and two endcaps). Also for example and as illustrated, the central axle 715 may include a cylindrical outer diameter.

Generally, the central axle 715 includes a member fixed to the compressor housing 710 at one or more locations. For example, the central axle 715 may include a member concentric with the center axis 95 and fixed to the compressor housing 710 at its aft and/or forward ends. Also for example, the central axle 715 may be solid, hollow, symmetrical, and/or asymmetrical. Accordingly, the central axle 715 may have a cylindrical shape, and be positioned in a location similar to that of a conventional drive shaft. However, unlike a conventional drive shaft, penetrating its respective compressor housing and operating at a high rotation speed, the driver central axle 715 may reside completely within the compressor housing 710, or at least be substantially sealed within the compressor housing 710.

According to one embodiment, the central axle 715 may be hollow or include hollow portions. In particular, the central axle 715 may include one or more passageways through which power, control, cooling, pressure equalization, etc. may be provided to or within the internal-driven compressor 700. For example, the central axle 715 may have a generally tubular shape. In addition, the central axle 715 may include an access port 719 at the endcap 718. As such, the external power supply interface 705 may be statically sealed at the access port 719, and power and signal cables may be routed through the fixed central axle 715. Also for example, the central axle 715 may ported such that equalization pressure may reach the balance piston cavity 717.

FIG. 3 is a schematically illustrated, cutaway side view of a portion of the internal-driven compressor of FIG. 2, illustrating an internal driver and a compressor bearing system. In particular, the internal driver 740 is shown integrated with the powered compressor rotor 730, and the compressor bearing system 750 is shown expanded to illustrate both radial and axial bearings. For clarity, single elements may be represented where multiple elements may be, and are used. In addition, the nose cover 721 and portions of the compressor housing 710 are removed (FIG. 2).

The internal driver 740 includes the rotor 741, the stator 742, and a driver anchor 743. Moreover, the internal driver 740 is configured as an inverted motor. In particular, and as illustrated, the stator 742 is radially inward of the rotor 741 (unlike conventional shaft-driven machines having their stator radially outward). Thus, the rotor 741 of the internal driver 740 is radially outward from the stator 742. Additionally, the rotor 741 may be integrated into the powered compressor rotor 730, and the stator 742 may be integrated with or into the central axle 715.

According to one embodiment, the internal driver 740 may be embodied as a permanent magnet (PM) electric motor. In particular, the rotor 741 may include permanent magnets, and the stator 742 may include motor stator coils, radially inward of the rotor 741. For example, the permanent magnets may be embedded in or otherwise fixed to the impeller bore surface 732, and the motor stator coils may be fixed to the central axle 715.

According to another embodiment, the internal driver 740 may be embodied as an induction or asynchronous motor. In particular, the rotor 741 may be a squirrel-cage rotor radially outward of the stator winding of its stator 742. For example, the squirrel-cage may be embedded in or otherwise fixed to the impeller bore surface 732, and the stator winding may be fixed to the central axle 715.

The internal driver 740 may further include a power supply 744 and a driver control system 745. The power supply 744 includes a power conduit such as a high voltage DC cable or a multi-phase AC power cable. The power supply 744 is coupled to the external power supply interface 705 (FIG. 1) and the powered components of the stator 742, as well as any associated hardware or controllers.

Similarly, the driver control system 745 includes a communications link between the external power supply interface 705 and the internal driver 740. The communications link may include a conventional communications link such as a wired, industrial bus communications link. In addition, the driver control system 745 may include feedback sensors, onboard controllers, and/or other hardware associated with feedback and control of the internal driver 740.

Both the power supply 744 and the driver control system 745 may be installed in and routed through the central axle 715. In particular, cabled or wired portions of the power supply 744 and the driver control system 745 may couple with the internal-driven compressor 700 at the external power supply interface 705, and enter the compressor housing 710 by means of the access port 719 (statically sealed penetrator) in the endcap 718 (pressure vessel wall). For convenience, wired portions of the power supply 744 and the driver control system 745 are illustrated as being integrated in a single harness, but might also be separated to avoid cross-talk, for example.

The driver anchor 743 is an interface fixing the stator 742 to the compressor housing 710. In particular, the driver anchor 743 provides a counteracting force to the internal driver 740 in order to impart rotation to the powered compressor rotor 730. The driver anchor 743 may be a discrete component, or may be integrated with or distributed across other components. For example, the driver anchor 743 may be integrated with central axle 715, wherein the stator 742 is non-rotatably fixed to the central axle 715, and the central axle 715 is non-rotatably fixed to the to the compressor housing 710. To illustrate, here, the motor stator coils of the stator 742 are fixed to the central axle 715, and the central axle 715 is embodied as a spindle or central stub axle non-rotatably mounted to the compressor housing 710 at the endcap 718. Alternately, the central axle 715 may be formed from, or otherwise be part of, the compressor housing 710.

The compressor bearing system 750 may include radial bearings configured to rotatably support the powered compressor rotor 730 about the center axis 95. In particular, the radial bearings may include a suction end radial bearing 751 axially located forward of the internal driver 740, and a discharge end radial bearing 752 axially located aft of the internal driver 740. Additionally, the suction end radial bearing 751 and the discharge end radial bearing 752 may be axially positioned at extreme ends of the powered compressor rotor 730 so as to provide maximum stability. Moreover, portions of the suction end radial bearing 751 and the discharge end radial bearing 752 may be mounted to the powered compressor rotor 730 while other portions are mounted to the central axle 715. For example, the suction end radial bearing 751 and the discharge end radial bearing 752 may be mounted with an interference fit. In one embodiment radial bearings are thermally installed.

The compressor bearing system 750 may further include a thrust bearing 753 (axial bearing) configured to support and/or balance the powered compressor rotor 730 against axially loading. In particular, the thrust bearing 753 may provide a bearing force against the powered compressor rotor 730 in one or both axial directions during rotation. For example, the powered compressor rotor 730 may further include a thrust collar 739 that extends radially inward from the powered compressor rotor 730, and the thrust bearing 753 may provide an axial force against the thrust collar 739 while allowing for its rotation.

The thrust bearing 753 may support the powered compressor rotor 730 independently, or in combination with (assisted by) the balance piston 736. In addition, the thrust bearing 753 may be axially located between the suction end radial bearing 751 and the discharge end radial bearing 752.

According to one embodiment, the compressor bearing system 750 may include conventional mechanical bearings. In particular, the compressor bearing system 750 may self-contained and directly support the radial and axial loading. For example, the mechanical bearings maybe rolling-element bearings such as ball bearings or roller bearings. In addition, the rolling-element bearings may be lubricated and sealed.

According to another embodiment, the compressor bearing system 750 may include magnetic bearings, in which the load is carried by a magnetic field. In particular, the powered compressor rotor 730 is mounted on to the central axle 715 by means of two inverted radial active magnetic bearings (AMBs). The AMBs are configured to magnetically levitate the powered compressor rotor 730 and/or the thrust collar 739, within a gap therebetween, and with very low friction and no mechanical wear. For example, in the embodiment shown, the suction end radial bearing 751, the discharge end radial bearing 752, and the thrust bearing 753 are AMBs. The powered compressor rotor 730 may include at least one magnetic bearing rotor fixed to and located within a radially inward portion of the annular body 731, the at least one magnetic bearing rotor configured to levitate the powered impeller about a magnetic bearing stator located radially inward of the at least one magnetic bearing rotor.

Similar to the internal driver 740, the inverted AMBs may be configured with coils on the central axle 715, a laminated sleeve on the outside of the coils. There are AMBs with permanent magnets (homopolar bearings) that enhance the action of the coil. In one embodiment, the suction end radial bearing 751 and the discharge end radial bearing 752 may include permanent magnets. Also, in the embodiment depicted, the thrust bearing 753 is located axially aft of the internal driver 740 and proximal to the discharge end radial bearing 752. However, the thrust bearing 753 may be located at any axial position on the powered compressor rotor 730, including axially forward and proximal to the suction end radial bearing 751. In one embodiment, the thrust bearing 753 may include permanent magnets.

The compressor bearing system 750 may further include a bearing power supply 755 and a bearing control system 756. The bearing power supply 755 includes a power conduit configured to supply operational power to the AMBs of the compressor bearing system 750. The bearing power supply 755 is coupled to the external power supply interface 705 (FIG. 1) and the AMBs, as well as any associated hardware or controllers.

Similarly, the bearing control system 756 includes a communications link between the external power supply interface 705 and the compressor bearing system 750. The communications link may be a conventional communications link such as a wired, industrial bus communications link. In addition, the bearing control system 756 may include feedback sensors, onboard controllers, and/or other hardware associated with feedback and control of the compressor bearing system 750.

For example, the bearing control system 756 may include one or more radial position sensors 757 and axial position sensors 758. The radial position sensors 757 may be configured to measure AMB gap or radial position at the suction end radial bearing 751 and at the discharge end radial bearing 752. Moreover, each AMB may have a plurality of radial position sensors 757.

Similarly, the axial position sensors 758 may be configured to measure axial position of the powered compressor rotor 730. For example, one or more axial position sensors 758 may be located proximate the thrust collar 739, and measure the axial position of the thrust collar 739 or the gap between one side of the thrust collar 739 and each AMB of the thrust bearing 753, respectively.

Both the bearing power supply 755 and the bearing control system 756 may be installed in and routed through the central axle 715. In particular, cabled or wired portions of the bearing power supply 755 and the bearing control system 756 may couple with external power or controllers at the external power supply interface 705, and enter the compressor housing 710 by means of the access port 719 (statically sealed penetrator) in the endcap 718 (pressure vessel wall). From the access port 719, the cabled or wired portions may extend to and interface with their respective internal portions of the bearing control system 756. For convenience, wired portions of the bearing power supply 755 and the bearing control system 756 are illustrated as being integrated in a single harness, but might also be run separately to avoid cross-talk, for example.

Additionally, the compressor bearing system 750 may include a combination of magnetic bearings and mechanical bearings (e.g., rolling-element bearings, plain bearings, hardened contact surfaces, etc.). In particular, the compressor bearing system 750 may also include auxiliary or backup bearings. For example, the compressor bearing system 750 may include the magnetic bearings as primary or operational bearings, and further include auxiliary or back up bearings operable in the event of power loss, wherein the auxiliary bearings may be mechanical bearings. Also for example, the auxiliary bearings ((e.g., rotating element bearings) provide support for the powered compressor rotor 730 during standstill, AMB transient conditions, or other periods where power may be unavailable or intermittent (e.g., test, maintenance, etc.).

FIG. 4 is a schematically illustrated, cutaway side view of a portion of the internal-driven compressor of FIG. 2, illustrating an internal driver cooling system. Here, the abovementioned power and control features of the internal driver 740 and the compressor bearing system 750 have been left out or simplified for clarity purposes and ease of explanation.

According to one embodiment, the internal-driven compressor 700 may further include an internal driver cooling system 780. In general, the internal driver cooling system 780 includes a cooling circuit configured to receive a portion of the working fluid, exchange heat from the powered impeller to the portion of the working fluid, and discharge the portion of the working fluid from the powered impeller. Thus, here, the internal driver cooling system 780 is configured to cool the internal driver 740 using its own compressed gas.

For example, the internal driver cooling system 780 may supply the compressed gas into the central axle 715, distribute the compressed gas to the internal driver 740 (heating the compressed gas), and discharge the heated compressed gas. In addition the internal driver cooling system 780 may distribute the compressed gas to the compressor bearing system 750 for cooling. Moreover, the internal driver cooling system 780 may circulate the compressed gas of the internal-driven compressor 700 as its coolant.

According to one embodiment, the internal driver cooling system 780 may include a discharge tap 781, a cooling line 782, a manifold 783, a return line 784, and a suction outlet 785. The discharge tap 781 may be an opening in, or port to, the compressor flow path downstream of the powered compressor rotor 730, providing access to the gas after it is compressed. For example, the discharge tap 781 may be located in a portion of the compressor outlet 725 such as in the collector 727 (e.g., piercing the discharge volute). The discharge tap 781 may be positioned such that cooling gas is bled off at discharge pressure (Pd) or at maximum recovery pressure.

The cooling line 782 may be any suitable line or conduit, pneumatically coupled to the discharge tap 781, and configured to route the cooling gas to the manifold 783. The cooling line 782 may enter the central axle 715 via the access port 719. Also, the cooling line 782 may include one or more passageways through the compressor housing 710 or other structures therein.

Generally, the cooling line 782 is a pressurized gas conduit configured to route pressurized cooling gas from the discharge tap 781 to the central axle 715. For example, cooling line 782 may include standard stainless steel tubing and any associated routing hardware. The cooling line 782 may be segmented, integrated into other passageways, distributed across additional cooling system components (e.g., discussed below), or any combination thereof.

The manifold 783 is pneumatically coupled to the cooling line 782 or otherwise integrated into the cooling circuit. Generally, the manifold 783 is a pressurized gas conduit configured to receive, route, and distribute the pressurized cooling gas from the cooling line 782 to the components or regions of the internal-driven compressor 700 to be cooled (e.g., the internal driver 740, the compressor bearing system 750, and their surroundings). For example, the manifold 783 may distribute the pressurized cooling gas to appropriate openings in the central axle 715 through the stator 742 and the rotor/stator gap 746 of the internal driver 740, the AMBs, etc.

Similar to the cooling line 782, the manifold 783 may be embodied as a discrete component, as a series of passageways through another component or structure, or a combination thereof. For example, at least a portion of the manifold 783 may include a tubing network within the central axle 715. Also for example, at least a portion of the manifold 783 may include a combination of passageways or cavities in the central axle 715 or ports therethrough, configured to strategically inject cooling gas into the components or regions of the internal-driven compressor 700 to be cooled.

The return line 784 and the suction outlet 785 are analogous to the cooling line 782 and the discharge tap 781, except they are configured to return “used” or heated gas back to the compressor flow path, and upstream of the powered compressor rotor 730. For example, the suction outlet 785 may be positioned proximate the suction end 97 of the internal-driven compressor 700, and the return line 784 may be a dedicated line to the suction outlet 785.

Moreover, the return line 784 may be integrated with the balance piston 736 such that the heated gas is discharged to the balance piston cavity 717 and the return line 784 ports the balance piston cavity 717 to the lower pressure supply at the suction outlet 785. Alternately, as illustrated in FIG. 4, the return line 784 may include a series of pneumatic links through the central axle 715 terminating in an upstream opening such that heated gas is returned and the balance piston cavity 717 may be ported to a lower pressure supply via a cooling system.

The internal driver cooling system 780 may further include pre-conditioning features for the cooling gas. In particular, the internal driver cooling system 780 may include a gas filter 786, a flow meter 787, and/or a heat exchanger 788. Moreover, the pre-conditioning features may be pneumatically interspersed between the discharge tap 781 and the components or regions to be cooled along the cooling line 782. The pre-conditioning features may be arranged as illustrated, of in another order.

According to one embodiment, the flow meter 787 may be a pressure regulating valve or orifice configured to limit or meter the flow of the cooling gas at a pressure slightly above suction pressure. Also, the heat exchanger 788 may include an external cooling loop to further reduce the temperature of the cooling gas below that of the discharge temperature of the internal-driven compressor 700.

Separately, intercooling as a means of limiting the gas discharge temperature and improving thermodynamic efficiency may be easily achieved by stacking multiple single or double-stage machines in series with the heat exchanger 788.

FIG. 5 is a schematically illustrated, cutaway side view of an exemplary two-stage internal-driven compressor. In particular, the illustrated two-stage internal-driven compressor 701 is embodied as a radially-fed, centrifugal gas compressor having a side discharge. Here, each powered impeller represents a single stage of compression having independent rotation (discussed below). In alternate embodiments, a plurality of impellers may be fixed together with a bearing arrangement of a single stage but without having independent rotation.

As shown, the gas 15 enters the two-stage internal-driven compressor 701 radially, is compressed in two stages, and is subsequently collected and discharged. As above, various components and surfaces have been left out or simplified for clarity purposes and ease of explanation. For example, the two stages of the two-stage internal-driven compressor 701 are shown with a simplified bearing arrangement.

In this embodiment, the two-stage internal-driven compressor 701 includes a radial compressor inlet 620. The radial compressor inlet 620 is a generally annular duct that receives gas 15 from a suction port (not shown) in a radial direction, redirects it into an axial flow along an annular path, and routes it to a first stage inlet 621. In an alternate embodiment, the two-stage internal-driven compressor 701 may include an axial compressor inlet similar to FIG. 1, instead of the radial compressor inlet 620.

The two-stage internal-driven compressor 701 includes a first stage section 601, a last stage section 603, and a diaphragm section 660. The first stage section 601 is located upstream of the last stage section 603. The first stage section 601 and the last stage section 603 are coupled together via the diaphragm section 660. The diaphragm section 660 routes a radial flow discharged from the first stage section 601 into the last stage section 603 as an axial flow.

Generally, the first stage section 601 and the last stage section 603 may include the same or similar features as in the single-stage embodiment of the internal-driven compressor 700 described above. In particular, the first stage section 601 and the last stage section 603 each include a powered impeller, an internal driver, and a compressor bearing system similar to the internal-driven compressor 700 described above.

Furthermore, the first stage section 601 may include a first stage central axle 611, and the last stage section 603 may include a last stage central axle 613. The first stage central axle 611 and the last stage central axle 613 may be similar to the central axle 715 of the single-stage embodiment, and include similar features as described above. In the two-stage configuration, the first stage central axle 611 and the last stage central axle 613 may be cantilevered, joined together, or independently supported at each outboard end and jointly supported at their inboard ends.

In addition, the first stage section 601 and the last stage section 603 may each include a driver harness 644 and a bearing harness 655. For convenience, the power supply and the driver control system, are represented here as the driver harness 644, and the bearing power supply and the bearing control system are represented here as the bearing harness 655, however, the driver harness 644 and the bearing harness 655 may each be separated into its individual components, as in the single-stage embodiment of the internal-driven compressor 700. Each driver harness 644 and bearing harness 655 may be installed in and routed through its respective central axle 611, 613, similar to the single-stage embodiment of the internal-driven compressor 700.

According to one embodiment, the two-stage internal-driven compressor 701 may include independent power and control lines for each stage. In particular, the first stage section 601 may have dedicated power and control lines that are separated and differ in their plumbing from those of the last stage section 603 (and the internal-driven compressor 700 described above). For example, in the first stage section 601, the driver harness 644 and the bearing harness 655 enter the first stage central axle 611 by means of an access port 617 in an endcap 616 on the suction end 97. In contrast, in the last stage section 603, the driver harness 644 and the bearing harness 655 enter the last stage central axle 613 by means of the access port 619 in the endcap 618 on the discharge end 98. In alternate embodiments, the lines may be plumbed at a single end, through one section, and onto another section.

The diaphragm section 660 may include conventional features such as a diffuser 661, a turnaround 662, a diaphragm bulb 663, and a plurality of return vanes 664. The diffuser 661 extends from a downstream end of a first stage powered impeller 631. The turnaround 662 extends from the diffuser 661 to the first stage inlet 621. Together, the diffuser 661 and the turnaround 662, inter alia, pneumatically couple the radial outlet of the first stage section 601 and axial inlet of the last stage section 603, completing the compressor flow path therebetween. The diaphragm flow path may circumscribe the center axis 95.

The plurality of return vanes 664 are distributed in the compressor flow path about the center axis 95. In particular, the plurality of return vanes 664 may be radially distributed in the turnaround 662 about the center axis 95. The plurality of return vanes 664 may be configured, inter alia, to by reducing swirl in the gas 15 before entering the last stage section 603.

The diffuser 661 and the turnaround 662 may be formed by inner surfaces of the compressor housing downstream of a first stage powered impeller 631, and by outer surfaces of the diaphragm bulb 663. The diaphragm bulb 663 may be supported, at least in part, by the plurality of return vanes 664. For example, the plurality of return vanes 664 may include interior bores or passageways through which fasteners, such as mounting bolts, may pass and attach to the diaphragm bulb 663.

According to one embodiment, the two-stage internal-driven compressor 701 may be configured for independent rotation of the individual stages. In particular, the first stage powered impeller 631 may be rotatably decoupled from a last stage powered impeller 633, and configured to rotate independently (e.g., at a different angular velocity). For example, the first stage powered impeller 631 may be supported by a first stage bearing system 651 and driven by a first stage internal driver 641. Likewise, the last stage powered impeller 633 may be supported by a last stage bearing system 653 and be driven by a last stage internal driver 643. In this embodiment, the drive and bearing systems of each stage may be physically decoupled from each other, and have independent power and control. For example, each stage may have its own independent 5-axis AMB controller (4 radial, 1 axial), and its own variable frequency drive (VFD).

According to one embodiment, the first stage section 601 and the last stage section 603 may also include independent, internal driver cooling systems similar to the of the single-stage embodiment described above. In particular, the first stage section 601 may include a first stage cooling system configured to tap gas 15 from the diaphragm section 660, and the last stage section 603 may include a last stage cooling system configured to tap gas 15 from the compressor outlet 625. Alternately, the two-stage internal-driven compressor 701 may include a shared cooling system.

FIG. 6 is a schematically illustrated, cutaway side view of an exemplary multi-stage internal-driven compressor. In particular, the illustrated multi-stage internal-driven compressor 702 is also embodied as a radially-fed, centrifugal gas compressor having a side discharge. Here, the multi-stage internal-driven compressor 702 includes three powered impellers 630 providing three stages of compression, with each having independent rotation. In alternate embodiments, a plurality of impellers may be fixed together with a bearing arrangement of a single stage but without having independent rotation.

The multi-stage internal-driven compressor 702 may include the basic components described in FIG. 5, plus one or more intermediate stages. In particular, the multi-stage internal-driven compressor 702 includes the first stage section 601, the last stage section 603, and the diaphragm section 660 as described above. In addition, the multi-stage internal-driven compressor 702 includes an intermediate stage section 602, and a plumbed diaphragm section 670.

The intermediate stage section 602 is substantially similar to the first stage section 601 above. In particular, the intermediate stage section 602 includes an intermediate stage powered impeller 632, an intermediate stage internal driver 642, an intermediate stage compressor bearing system 652, and an intermediate stage central axle 612, all are similar to their analogous components of the first stage section 601 described above. The intermediate stage section 602 may also include an interior driver harness 645, an interior bearing harness 656, and an interior cooling system (not shown), which are similar to the driver harness 644, the bearing harness 655, and internal driver cooling system 780 above, respectively.

The plumbed diaphragm section 670 is similar to the diaphragm section 660; however, the plumbed diaphragm section 670 also includes one or more passageways extending from intermediate stage central axle 612 out of the plumbed diaphragm section 670. In particular, the plumbed diaphragm section 670 may include conventional features such as a diffuser 671, a turnaround 672, a diaphragm bulb 673, and a plurality of return vanes 674. However, the plumbed diaphragm section 670 may further include one or more passageways configured to route the interior driver harness 645, the interior bearing harness 656, and/or components of the interior cooling system out from the intermediate stage section 602.

For example, plumbed diaphragm section 670 may also include a rotor interface 675, a diaphragm bulb path 676, a return vane path 677, and a diaphragm outlet 678. The rotor interface 675 may include a cavity and an opening in the diaphragm bulb 673 that interfaces with an interior portion of the intermediate stage section 602. The diaphragm bulb path 676 is a passageway through the diaphragm bulb 673 to the return vane path 677. The return vane path 677 is a passageway though at least one return vane 674 to the diaphragm outlet 678.

As illustrated, the multi-stage internal-driven compressor 702 begins with the radial compressor inlet 620 at its suction end 97. Continuing downstream, the radial compressor inlet 620 is coupled to the first stage section 601, which is in turn coupled to the diaphragm section 660, which is in turn coupled to the intermediate stage section 602, which is turn coupled to plumbed diaphragm section 670, which is in turn coupled to the last stage section 603, which is coupled to and terminates with the compressor outlet 625.

Accordingly, the multi-stage internal-driven compressor 702 may be substantially similar to the two-stage embodiment above with the intermediate stage section 602 coupled to plumbed diaphragm section 670 and interspersed between the diaphragm section 660 and the last stage section 603. Moreover, the multi-stage internal-driven compressor 702 may be expanded to include additional stages by adding additional intermediate stage sections 602 coupled to additional plumbed diaphragm sections 670.

As above, conduit for the driver harness 644, the bearing harness 655, and/or the internal driver cooling system 780 (FIG. 4) of the first stage section 601 may exit the first stage central axle 611 via the access port 617 on the suction end 97. Likewise, conduit for the driver harness 644, the bearing harness 655, and/or the internal driver cooling system 780 of the last stage section 603 may exit the last stage central axle 613 via the access port 619 on the discharge end 98. For each intermediate stage section 602, conduit for the interior driver harness 645, the interior bearing harness 656, and/or the interior cooling system (not shown), may exit the intermediate stage central axle 612 via its diaphragm outlet 678.

According to one embodiment, the multi-stage internal-driven compressor 702 may include additional stages. In particular, although the multi-stage internal-driven compressor 702 is embodied here as having three stages, additional intermediate stage sections 602 may be added. For example, the multi-stage internal-driven compressor 702 may include a plurality of intermediate stage sections 602 coupled to each other, and providing additional compression stages.

As above, the multi-stage internal-driven compressor 702 may be configured for independent rotation of the individual stages. In particular, one or more stages may be rotatably decoupled such that they may rotate independently of each other. Likewise, the drive and bearing systems of each stage may be physically decoupled from each other, and have independent power and control. Alternately, one or more of the powered impellers 630 may be rotatably coupled to each other such that they have uniform rotation or dependent rotation. Thus, the multi-stage internal-driven compressor 702 may include stages that are independent and stages that are dependent or coupled.

INDUSTRIAL APPLICABILITY

The present disclosure generally applies to an integrated power supply in an industrial compressor, particularly an industrial gas compressor. The described embodiments are not limited, however, to use in conjunction with a particular type of gas compressor (e.g., centrifugal, axial, etc.). Gas compressors such as centrifugal gas compressors are used to move process gas from one location to another. Centrifugal gas compressors are often used in the oil and gas industries to move natural gas in a processing plant or in a pipeline. Centrifugal gas compressors are driven by gas turbine engines, electric motors, or any other power source.

Depending on the model, industrial gas compressors may have from 1-12 stages to handle a variety of inlet flows and pressure ratios. Industrial gas compressors can produce ratios of over 5:1 while multiple, tandem-mounted compressors can produce pressure ratios approaching 40:1. In addition, industrial gas compressors may be compliant with API 617 for rugged and reliable operation. The modular industrial gas compressor design simplifies restaging industrial gas compressors to meet changing field conditions. Embodied as an industrial gas compressor, the internal-driven compressor 700 may have a maximum gas flow of 1300 cubic meters/minute, at least 50 cubic meters/minute, between 50-1300 cubic meters/minute, between 250-500 cubic meters/minute, and between 300-700 cubic meters/minute, for example. Similarly, embodied as an industrial gas compressor, the internal-driven compressor 700 may have a pressure rating of 30,000 kPa, at least 10,000 kPa, between 10,000-30,000 kPa, between 11,000-21,000 kPa, and between 20,000-26,000 kPa, for example. Similarly, embodied as an industrial gas compressor, the internal-driven compressor 700 may have a maximum head of 275 kJ/kg, at least 100 kJ/kg, between 100-275 kJ/kg, between 100-210 kJ/kg, and between 200-260 kJ/kg, for example. Similarly, embodied as an industrial gas compressor, the internal-driven compressor 700 may have a maximum speed of 24,000 rpm, at least 7,000 rpm, between 7,000-24,000 rpm, between 10,000-12,500 rpm, and between 12,000-17,000 rpm, for example

The internal-driven compressor 700 forms a compressor flow path where the gas 15 is received by the compressor inlet 720, compressed and propelled by the powered compressor rotor 730, and discharged by the compressor outlet 725. In operation, gas 15 enters the compressor inlet 720 at the suction end 97, is compressed in the one or more stages, and is diffused, collected, and discharged at the compressor outlet 725. Power (e.g., electric power) is provided to the internal-driven compressor 700 via its external power supply interface 705 from an external source (e.g., grid, local generator, Variable Frequency Drive VFD, etc.). In addition, communications of control signals, feedback signals, etc. may also go through the external power supply interface 705 or another communication link.

Internally, the power is provided to the internal driver 740, which then rotates the powered compressor rotor 730 through the interaction of its stator 742 mounted to the central axle 715, for example, and its rotor 741 embedded in the powered compressor rotor 730, for example. In addition, power may be provided to the compressor bearing system 750 (where AMBs are used). Both the internal driver 740 and the compressor bearing system 750 may be controlled locally or remotely using their respective control systems and harnesses (communication links). As discussed above, one or more stages may be independently rotatable. Accordingly, each stage may be statically adjusted for its particular flow parameters within the system. In addition, each stage may be dynamically adjusted upon detection of transient conditions such as surges.

In some instances, embodiments of the presently disclosed internal-driven compressor having a powered compressor rotor are applicable to the use, operation, maintenance, repair, and improvement of centrifugal gas compressors, and may be used in order to improve performance and efficiency, decrease maintenance and repair, and/or lower costs. In addition, embodiments of the presently disclosed control system may be applicable at any stage of the centrifugal gas compressor's life, from design to prototyping and first manufacture, and onward to end of life. Accordingly, internal-driven compressor may be used in conjunction with a retrofit or enhancement to existing centrifugal gas compressors, as a preventative measure, or even in response to an event.

More specifically, internal-driven compressor having a powered compressor rotor may be beneficial in improved rotor dynamics, robustness, and performance. The inclusion of the powered compressor rotor or powered impeller may significantly reduce the axial length of the compression device by making both the driver and the rotor concentric and colocational. In this way, many rotor dynamic complications may be reduced or eliminated. The inclusion of magnetic bearings may further enhance control and balance associated with the compressor's rotor dynamics. The inclusion of magnetic bearings may also provide for greater efficiencies and reduced emissions while realizing the synergistic benefits of a shared power supply (i.e., where the internal driver is also electrically powered).

Also, since there is no rotating shaft penetrating the compressor housing the external power supply interface may be statically sealed to the compressor housing. This may provide for use in applications having harsh operating environments (e.g., submerged, pressurized, abrasive/corrosive, etc.), as well as clean environments. This may also be used in gas applications having harsh gas constituents (chemically active gases, water, solids).

Moreover, the additional components associated with a shaft coupling may be eliminated, and reducing unnecessary subsystems may reduce overall cost. Likewise, design and maintenance challenges for dynamic seals may be mitigated by this innovation. In addition, the internal-driven compressor may have a smaller footprint and the “all inclusive” design may be useful in sea floor application, particularly where the shaft does not require oil.

Performance may be improved by the powered compressor rotors being decoupled and having independent rotation. As above, potentially every compression stage may be individually operated and controlled. When used in a multi-stage configuration, new compression configurations are possible due to the free choice of speeds for each stage. In addition, the internal-driven compressor may be combined with an appropriate anti-surge controller for improved operating range due to the ability of adapting independent impeller speeds to overcome local surge conditions.

The preceding detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. The described embodiments are not limited to use in conjunction with a particular type or combination of driver and driven machine. For example, the driver may be an electric motor, a hydraulic motor, a pneumatic motor, or other compact rotating machine. Also for example the driven machine may be a gas compressor, a pump, a refrigerant compressor or other rotatingly driven machine. Hence, although the present embodiments are, for convenience of explanation, depicted and described as being implemented in a centrifugal gas compressor driven by an electric motor, it will be appreciated that it can be implemented in various other types of drivers and driven machines, and in various other systems and environments. Furthermore, there is no intention to be bound by any theory presented in any preceding section. It is also understood that the illustrations may include exaggerated dimensions and graphical representation to better illustrate the referenced items shown, and are not considered limiting unless expressly stated as such. 

What is claimed is:
 1. An industrial gas compressor comprising: a compressor housing including a suction port and a discharge port; an internal driver including a rotor and a stator, the rotor and the stator located within the compressor housing, the stator located radially inward of the rotor; and a powered compressor rotor including an annular body extending about a center axis; and wherein the rotor is fixed to the powered compressor rotor and is configured to rotate the powered compressor rotor about the center axis in response to a force imparted by the stator.
 2. The industrial gas compressor of claim 1, further comprising a central axle nonrotatably fixed to the compressor housing and configured to support the internal driver and the powered compressor rotor; and a compressor bearing system, the compressor bearing system including one or more magnetic bearings fixed to the central axle, and configured to rotatably support the powered compressor rotor about the center axis.
 3. The industrial gas compressor of claim 1, wherein the powered compressor rotor is further configured to compress a gas, the industrial gas compressor further comprising an internal driver cooling system, the internal driver cooling system configured to receive a portion of the gas, to exchange heat from at least one of the internal driver and the powered compressor rotor to the portion of the gas, and to subsequently discharge the portion of the gas from the internal driver cooling system.
 4. The industrial gas compressor of claim 1, wherein the compressor housing includes a balance piston cavity; and wherein the powered compressor rotor further includes an impeller bore surface and a series of impeller vanes configured to rotate about the center axis, the impeller bore surface circumscribing the stator, and further includes a balance piston, the balance piston including a balance piston seal and a piston head, the balance piston set in the balance piston cavity.
 5. The industrial gas compressor of claim 1, wherein the industrial gas compressor has at least two stages of compression and a maximum gas flow between 50-1300 cubic meters/minute.
 6. An internal-driven compressor comprising: a compressor housing; an internal driver including a rotor and a stator, the rotor and the stator located within the compressor housing, the stator located radially inward of the rotor; and a powered compressor rotor including an annular body extending about a center axis, an impeller bore surface, and a series of impeller vanes configured to rotate about the center axis, the impeller bore surface circumscribing the stator; wherein the rotor is fixed to and located within the impeller bore surface, and the rotor is configured to rotate the powered compressor rotor about the center axis in response to a force imparted by the stator.
 7. The internal-driven compressor of claim 6, further comprising: an external power supply interface including a power conduit configured to receive electrical power from an external power source and provide the electrical power into the internal-driven compressor; a central axle fixed to the compressor housing and configured to support the internal driver and the powered compressor rotor, the central axle including at least one internal passageway, the at least one internal passageway including an access port; a compressor inlet configured to receive a gas into the internal-driven compressor; and a compressor outlet configured to discharge the gas from the internal-driven compressor; and wherein the internal driver further includes a power supply extending from the internal driver through the at least one internal passageway of the central axle and the access port.
 8. The internal-driven compressor of claim 6, further comprising a compressor bearing system, the compressor bearing system including one or more magnetic bearings fixed to the central axle, and configured to rotatably support the powered compressor rotor about the center axis.
 9. The internal-driven compressor of claim 6, wherein the compressor housing includes a balance piston cavity; and wherein the powered compressor rotor further includes a balance piston, the balance piston including a balance piston seal and a piston head, the balance piston set in the balance piston cavity.
 10. The internal-driven compressor of claim 6, wherein the internal driver is a permanent magnet electric motor, the rotor including permanent magnets, and the stator including motor stator coils.
 11. The internal-driven compressor of claim 6, wherein the powered compressor rotor is further configured to compress a gas, the internal-driven compressor further comprising an internal driver cooling system, the internal driver cooling system configured to receive a portion of the gas, to exchange heat from at least one of the internal driver and the powered compressor rotor to the portion of the gas, and to subsequently discharge the portion of the gas from the internal driver cooling system.
 12. The internal-driven compressor of claim 11, wherein the internal driver cooling system includes a discharge tap configured to tap the portion of the gas from downstream of the powered compressor rotor, a cooling line coupled to the discharge tap, a manifold coupled to the cooling line and configured to distribute the portion of the gas to the at least one of the internal driver and the powered compressor rotor, and a return line and a suction outlet configured to discharge the portion of the gas upstream of the powered compressor rotor.
 13. The internal-driven compressor of claim 12, wherein the compressor housing includes a balance piston cavity; wherein the powered compressor rotor further includes a balance piston at a downstream end of the powered compressor rotor, the balance piston set in the balance piston cavity; and wherein the return line pneumatically couples the balance piston cavity to the suction outlet.
 14. The internal-driven compressor of claim 6, wherein the internal driver and the powered compressor rotor are included in a last stage section, the powered compressor rotor configured as a last stage powered impeller, the internal-driven compressor further comprising a first stage section including a first stage internal driver and a first stage powered impeller, the first stage section located upstream of the last stage section; and a diaphragm section coupled to the first stage section and the last stage section, the diaphragm section configured to route a radial flow discharged from the first stage section into the last stage section as an axial flow; and wherein the first stage powered impeller is rotatably decoupled from the last stage powered impeller and configured to rotate independently.
 15. The internal-driven compressor of claim 6, wherein the internal driver and the powered compressor rotor are included in a last stage section, the powered compressor rotor configured as a last stage powered impeller, the internal-driven compressor further comprising: a first stage section including a first stage powered impeller supported by a first stage central axle and driven by a first stage internal driver and; a diaphragm section coupled to and located downstream of the first stage section, the diaphragm section configured to route a first radial flow discharged from the first stage section into an first axial flow; an intermediate stage section coupled to and located downstream of the diaphragm section, the intermediate stage section including an intermediate stage powered impeller supported by an intermediate stage central axle and driven by an intermediate stage internal driver; and a plumbed diaphragm section coupled to and located downstream of the last stage section, the plumbed diaphragm section configured to route a second radial flow discharged from the intermediate stage section into an second axial flow, the plumbed diaphragm section including a passageway extending from the intermediate stage central axle out of the plumbed diaphragm section.
 16. The internal-driven compressor of claim 15, wherein the plumbed diaphragm section includes a flow path configured to pneumatically couple a radial outlet of the intermediate stage section to an axial inlet of the last stage section, the flow path circumscribing the center axis, a plurality of return vanes distributed in the flow path about the center axis, at least one of the plurality of return vanes including a return vane path, the return vane path being a first portion of the passageway, the first portion of the passageway extending into of the plumbed diaphragm section from a diaphragm outlet, and a diaphragm bulb including a diaphragm bulb path, the diaphragm bulb path being a second portion of the passageway, the second portion of the passageway extending from the first portion of the passageway to the intermediate stage central axle at a rotor interface, the rotor interface including a cavity and an opening in the diaphragm bulb that interfaces with a radially interior portion of the intermediate stage section.
 17. A powered compressor rotor assembly for an internal-driven compressor, the powered compressor rotor assembly comprising: a powered compressor rotor including an annular body with a center axis, the annular body having an impeller bore with an impeller bore surface about the center axis, the powered compressor rotor further including a series of impeller vanes extending from the annular body about the center axis; a central axle configured to support the powered compressor rotor, the central axle including at least one internal passageway, the at least one internal passageway including an access port; and an internal driver including a rotor and a stator, the rotor and the stator located within the powered compressor rotor, the stator located radially inward of the rotor relative to the center axis, wherein the rotor is fixed to and located within the powered compressor rotor and the stator is fixed to central axle.
 18. The powered compressor rotor assembly of claim 17, further comprising one or more radial bearings, one or more radial bearings fixed to the central axle and configured to rotatably support the powered compressor rotor about the center axis.
 19. The powered compressor rotor of claim 17, further comprising at least one magnetic bearing rotor fixed to and located within the impeller bore surface, the at least one magnetic bearing rotor configured to levitate the powered compressor rotor about a magnetic bearing stator located radially inward of the at least one magnetic bearing rotor; and wherein the motor rotor is axially located between a first magnetic bearing rotor and a second magnetic bearing rotor.
 20. The powered compressor rotor of claim 17, wherein the series of impeller vanes are ducted vanes having a shroud around the series of impeller vanes, the series of impeller vanes being radially underneath the shroud, the powered compressor rotor further comprising a shroud seal located on an outer circumference of the shroud. 